This project has two basic overall objectives: 1) To analyze lectin mediated human leukocyte chemotaxis, which we have recently described using a fucose binding lectin (FBL) in hopes of understanding the mechanism of chemotaxis and its relationship to membrane components and receptors; and 2) To utilize fucose binding Lotus tetragonolobus lectin, which our preliminary data indicate will bind to a species and granulocyte specific membrane determinant to clinically differentiate acute granulocytic from other acute leukemias. The latter objective will also include the study of leukocyte ontogeny with respect to the development of this granulocyte marker, and the presence of this determinant on functionally abnormal granulocytes. Chemotaxis will be studied using various different lectins in conjunction with fluorescent, radiolabel and EM techniques to determine the fate of surface lectin receptors during cell mobilization. Additional studies will assess the relationship of a lectin mediated chemotactic response to chemotaxis mediated by other chemotactic factors using enzyme release techniques, chemiluminescence and C-GMP assays. The ability of PMNs to regenerate lectin surface receptors and the relationship of these receptors to other known receptors (Fc, C3b, etc.) will be studied using fluorescent microscopy. These studies will help in understanding membrane and receptor function during the mobilization of cells to an inflammatory site. The second overall objective will utilize FBL isolated from Lotus tetragonolobus seeds to differentiate forms of leukemia. Fluorescent and radio-labeled FBL will first be used to quantitate the FBL receptor on the surface of normal PMNs. Preliminary studies, which indicate that FBL may be a practical means of diagnosing acute granulocytic leukemias, will be expanded to include more patients and compared to other means of differentiating acute leukemias. FBL will also be applied to the study of non-malignant but functionally abnormal granulocytes from patients currently under study here and having chemotactic and chemiluminescence disorders. These studies will aid in the understanding of the mechanism of leukocyte chemotaxis and can provide evidence for a unique granulocyte specific marker, the latter of which could be a valuable tool in classifying human granulocytic leukemias and investigating leukocyte differentiation.